condition mean min max ZT0-3 18.926183333333334 16.7402 20.59915 ZT4-7 18.53625 18.53625 18.53625 ZT8-11 16.56045 16.56045 16.56045 ZT12-15 29.065450000000002 26.002000000000002 32.1289 ZT16-19 23.274549999999998 23.274549999999998 23.274549999999998 ZT20-23 22.4 22.4 22.4